1. Field of the Invention
The present invention relates generally to systems for electrophotographically reproducing data on photosensitive film, and more particularly, to an apparatus for establishing electrical contact with the film while it is held on a carrier within an imaging apparatus.
2. Description of the Prior Art
Stimulated by the cost incurred in storing the everincreasing volume of documentary material which is presently being generated, considerable effort has been expended in the design and development of various electrophotographic and other data storage and retrieval systems. Particular emphasis has been placed on the design of microphotographic systems which may be used to decrease the physical bulk of such stored materials without sacrificing file retrieval and/or copy reproduction capabilities.
One type of apparatus for recording data on film for data storage is the indirect type of reproduction apparatus wherein a document is placed face down on a transparent platen and a light image is reflected from the document and directed by mirrors through a lens system and onto the film. This type of apparatus is disclosed in U.S. Pat. application Ser. No. 349,452, now Pat. No. 3,972,610, entitled Electrophotographic Method and Apparatus and filed Apr. 9, 1973 in the name of Frank C. Gross. In this type of system, the film, which is preferably a microfiche, must be securely held on the imaging axis at the proper focal length away from the lens system. Correct placement of the film is assured through use of a carrier having an alignment surface against which the film is firmly held when imaged. Since the carrier must be positioned inside of the enclosure of the photographic reproduction apparatus for imaging, it is not conveniently avialable for placement of a film, or microfiche, upon the carrier. This inconvenience is overcome by reciprocating the carrier to a load position near an opening of the enclosure and then back into the imaging position within the enclosure after placement of the film upon the carrier.
Conventional electrophotographic film in the form of microfiche is suitable for use in the apparatus described in U.S. Pat. application Ser. No. 349,452. Such film typically consists of a support layer having coated thereon a layer containing a suitable photoconductor. The support layer is made conductive by either the inclusion therein of electrically-conductive materials or by coating the support layer surface designed to receive the photoconductive layer with an electrically-conductive material. Images are formed on the photoconductive layer within the above-described reproduction apparatus by first applying a uniform electrostatic charge to the photoconductive layer and thereafter imaging the charged photoconductive layer by exposing it to light reflected from the document being reproduced, thereby causing the photoconductive layer to become conductive, which results in the dissipation of the charge in those areas of the photoconductive layer exposed to the light. In a subsequent step, the charge pattern or latent image on the photoconductive layer is rendered visible by the application thereto of colored or black electroscopic toner particles.
In operating the above-described reproduction apparatus, it is usually desirable during one or more of the processing steps, such as charging, imaging, or toning, to establish a ground connection (to a reference potential) or other electrical connection to the conductive layer of the film in order to create desirable electrical characteristics in the film. For this purpose, the film is usually provided with an electrically conductive area on the surface of the film. The electrically conductive area can be provided by filling a hole extending from the film surface to the conductive layer in a non-image area with an electrically-conductive composition, such as a mixture of plastic adhesive and electrically-conductive particles.
Some form of mechanical contacting means within the reproduction apparatus must be employed to make electrical contact with the conductive layer of the film and electrically interconnect it to the desired circuit, such as a ground. A number of techniques have been used, such as clips or clamps which are capable of engagement with the conductive area of the film, but they have generally lacked the ability of dependable electrical connection or have impeded placement and removal of the film on and from the carrier. Additionally, they usually have required manual operation to make the connection, which is inconvenient to the operator who needs free use of his hands to perform other chores attendant with recording information from documents.
In view of the disadvantages of the prior art, it is an object of the invention to provide electical connective means for establishing electrical contact with an electrically conductive area on the surface of an electrophotographic film. It is a further object of the invention to provide electrical connective means which will assure positive electrical contact with the electrically conductive area of the film without impeding placement or removal of the film on or from the carrier and without requiring manual operation.